Editor’s Note: In Part 2 of our series on the recission of the Endangerment Finding, Drs. Schiller and de Guzman continue a conversation about the consequences of the decision on cancer care. Part 1, Rescission of EPA Finding Prompts Concern About Impacts on Cancer Care, is available now.
In February 2026, the US Environmental Protection Agency (EPA) rescinded the Endangerment Finding of the Clean Air Act, the landmark 2009 ruling that established greenhouse gases as air pollutants and required the EPA to regulate them when they endanger public health or welfare. Why should this change in US policy concern an international society of thoracic oncologists and scientists?
Air pollution is driven largely by the burning of fossil fuels in vehicles and other engines, releasing toxic pollutants such as benzene, formaldehyde, and arsenic, as well as greenhouse gases, including carbon dioxide, nitrogen dioxide, methane, and fluorinated gases. A robust body of scientific evidence shows that these greenhouse gases trap heat from the sun, preventing it from escaping Earth’s atmosphere and warming the planet.
A hotter world is already reshaping health: more heat-related illness, trauma from extreme weather, rising seas that displace communities, growing food and water insecurity, and the spread of vector-borne diseases into new regions. At the same time, air pollution itself drives respiratory and cardiovascular disease, premature births, mental health disorders, and early death on a staggering scale.
Fine particulate matter smaller than the width of a human hair (PM2.5) has been classified by the International Agency for Research on Cancer as carcinogenic to humans. These particles penetrate deep into the lungs, enter the bloodstream, and trigger chronic local and systemic inflammation.
Air pollution and diesel particulate matter are recognized as Class 1 carcinogens, and it is incontrovertible that air pollution causes lung cancer—an estimated 14% of lung cancer deaths worldwide are attributed to it. There is an increasing number of cases of lung cancer in people who have never smoked, as well as early-onset lung cancers. Emerging data also link air pollution to breast, bladder, brain, and pediatric cancers, and to severe disruptions in access to cancer care during climate‑driven extreme weather events.
The 2026 repeal of the Endangerment Finding is already the subject of urgent legal challenges that may yet overturn this decision, but the damage from weakening protections is not confined to US borders. Air pollution, greenhouse gases, and climate change have global implications, and the EPA’s decision places every person in every country at greater risk from escalating climate change, rising disease burdens, and premature death tied to pollution. For people with cancer, these risks include delayed diagnoses, interrupted treatments, and poorer outcomes as climate impacts intensify.
Air Quality Policy is Cancer Care Policy
As physicians and health professionals, we have a profound moral responsibility to protect our patients from preventable disease. Nowhere is this clearer than in cancer, which claims more than 10 million lives each year worldwide.
If we allow additional greenhouse gas emissions, we will lock in even more hazardous warming and toxic air, guaranteeing higher cancer burdens and more frequent, deeper disruptions to cancer care. We must advocate for public policies that prioritize clean air and safeguard community health, lending our voices and expertise to efforts that drive meaningful change.
As cancer clinicians, we must consider the global implications of climate change to protect the future of our families, our children, and our patients. We must act locally, integrate environmental exposure histories into clinical care, and advocate for policies that protect public health.
In addition to individual patient care, we have a responsibility to educate our patients about the risks associated with poor air quality. Empowering patients with this knowledge enables them to make informed choices that protect their health.
Education on air quality, climate, and health must be integrated into medical training to prepare the next generation of clinicians to address the risks. At the institutional level, cancer centers can reduce their own carbon emissions, strengthen climate resilience in care delivery, and ensure continuity of treatment during extreme weather events.
Professional organizations also play a critical leadership role. They can issue evidence-based policy statements, develop clinical guidelines that incorporate environmental risk, and support environmental and climate health research.
Safeguarding the atmosphere is not a peripheral concern in cancer care; it is a fundamental component. It is prevention, it is equity, and it is the future of our field. The actions we take now will determine not only the future of cancer care, cancer burden, and cancer outcomes, but also the resilience of the systems we rely on to manage it.
